Kamala Harris launched a blistering attack on Donald Trump and his "extremist" Republicans as she addressed teachers Thursday, seeking to rally a key part of the Democratic coalition behind her bid to take on the billionaire for the presidency.
The country's first female vice president -- who is seeking to make history again in November -- has enjoyed a groundswell of support from labor groups, ethnic minorities and her own party since announcing her 11th-hour candidacy to replace President Joe Biden as the candidate.
The momentum appeared to catch Trump off guard, as the bombastic Republican refused to schedule a debate with Harris, saying Thursday night it would be "inappropriate" until she is officially named the Democratic nominee.
"Democrats very well could still change their minds," Trump campaign spokesman Steven Cheung said in a statement.
Harris, a former top prosecutor for California, chided on X: "What happened to 'any time, any place?'" Earlier she had said of a potential September 10 face-off: "I'm ready. So let's go."
The first union to endorse Harris -- the American Federation of Teachers -- applauded at their convention in Houston as Harris warned that the country was witnessing a "full-on attack" by Trump's Republicans on "hard-won, hard-fought freedoms."
"While you teach students about democracy and representative government, extremists attack the sacred freedom to vote. While you try to create safe and welcoming places where our children can learn, extremists attack our freedom to live safe from gun violence," she said.
"They have the nerve to tell teachers to strap on a gun in the classroom while they refuse to pass common sense gun safety laws."
Harris, 59, jumped into the election after weeks of turmoil over 81-year-old Biden, who bowed out Sunday after a dismal debate performance against Trump accelerated concerns over his mental capacity and persistently low polling numbers.
Calling herself "a proud product of public education," she connected her personal story to her political outlook, telling her audience that the work of teaching was "personal and it is professional, and... so critically important."
Harris tied the event to a key campaign message about refusing to go back to Trump's America, praising her audience as "visionaries" who look to the future.
And she contrasted Democratic efforts to cancel student debt and her vision of investment in public schools and universities with Trump's vow to dismantle the Education Department and cut spending in half.
- 'Freedom' -
Trump, who at 78 is the oldest presidential nominee in US history, has promised he will "not give one penny" of federal funds to schools with vaccine mandates. Every public school in America has such mandates.
The speech came with Harris facing increasingly extreme rhetoric from Trump, who on Wednesday called her a "radical left lunatic" and claimed -- entirely falsely -- that she was in favor of the "execution" of newborn babies.
Meanwhile Republicans in the House of Representatives passed a resolution Thursday criticizing Harris's record on immigration.
In a promising sign for Democrats, however, Trump and Harris were statistically tied in a new New York Times/Siena College poll that showed her narrowing the gap after the survey found Biden behind by six points in early July.
One of the most urgent tasks facing her in the much shorter term, however, is to forge her own political identity before she can be defined by Trump as inseparable from the unpopular Biden.
And she has begun quickly spending some of the $100 million-plus that she has raised in the opening days to tell her personal story and counter Republican characterizations of her as an out-of-touch liberal.
The Harris campaign sought to plant an early flag with its first TV spot Thursday -- an ad featuring the Beyonce hit "Freedom," warning that Americans' rights are under threat from the Trump agenda.
The speech came amid a mushrooming controversy over resurfaced remarks by Trump's vice-presidential candidate, J.D. Vance, who singled out Harris as he called Democrats a "bunch of childless cat ladies with miserable lives."
Harris has two stepchildren and the comments have sparked accusations that father-of-three Vance represents a backward Republican mindset.
Hollywood star Jennifer Aniston pointed to her own infertility while comedian and talk show host Whoopi Goldberg asked: "Now, what the hell?"